Their research questions society's strict definitions of sexuality and warns that we still struggle with the idea of bisexuality, especially when it comes to men.

Lead author Rich Savin-Williams suggests that sexuality exists on a spectrum and that younger generations are more open to the idea of fluid sexuality than older adults.

Both male and female volunteers were asked to watch porn involving men or women as part of the research.

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Tests found that women were turned on watching men and women having sex and by women and women having sex

Experts measured how much their pupils dilated - a sign of sexual arousal.

Women's eyes dilated watching both men with women and women with women.

And men's pupils dilated watching both men and women masturbate, regardless of how they identified sexually.

Savin-Williams warned that cultural expectations of sexuality need to change in order for people to be more comfortable with who they are attracted to.

"We've always recognised mostly straight women, that is, women who mostly are straight but if the right woman comes along, well maybe she'll try it out. We used to think that was only a female phenomenon," Savin-Williams told Broadly.

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The research warned that expectations of sexuality need to change in order for people to be more comfortable with who they are attracted to

"There are aspects [of male sexuality] along a continuum, just as we have always recognised with women.

"Men have gotten so much cultural c**p put on them that even if a man does have some sexual attraction to guys, they would never say it."